Sony has blamed hacking group Anonymous for being at least partially responsible for the data breach which resulted in the loss of personal information of potentially millions of customers.
Responding to pointed queries from the US authorities, Sony said that the firm had discovered a file called 'Anonymous' with the group's slogan 'We are Legion' inside.
In the response to the US House of Representatives, the firm said: "Sony has been the victim of a very carefully planned, very professional, highly sophisticated criminal cyber attack."
In response Anonymous issued a statement denying responsibility, calling Sony 'incompetent' and branding the accusation an attempt to 'distract users' from what the group described as a problem with Sony's internal servers.
"While it could be the case that other Anons have acted by themselves, AnonOps was not related to this incident and does not take responsibility for whatever has happened," said the Anonymous 'release'.